don't get frustrated...just think of it as a couple of months job..it takes time
Here is what helped me:
1. Inlaws!!! seriously, we were visiting my inlaws in IL and stayed there for a few days, during that time whenever I find that there is nothing for me to do I try to do work on the site.
2. as tessielou said use the copy function. I still do that for many of my items especially when trying to add the optional colors or going between my website and etsy store.
3. Do not be critical and spend hours listing one item. do what you can FAST, after the site is completed or whenever you find a mistake you can correct it.
4. do it in batches, for example I would spend a few hours on photoshop inhancing tens of pictures before I go to the website and add them instead of inhancing the picture one by one and then adding it to the site.
HTH and goodluck,